Switching from 250 to 350.

[TheSeeker]

Hello all, I have the chance to acquire my fathers 69 SWB. I found out last night that he is looking to get rid of it, anyway.. my current project and this truck are leaps and bounds apart. Mine is a 70 LWB that belonged to my grandfathers shop, and was in need of an entire teardown and rebuild. Its currently in peices...I have a GM crate 350 and a rebuilt th350 that was waiting to go into the 70 (originally a 350/350 combo. My dads 69 is a 250 inline with a 3 speed. My question is, I obviously dont want to let the fresh engine/tranny to go to waste and was thinking of of pulling the sixer to save for another project. What is the complete list of items and parts I would need to pull off the 70 in order to drop in the 350/th350. Thanks! Im excited to have my fathers SWB on the road after an engine swap, a brake job, and paint! (ps, my grandfathers pick up will go to my brother, whose been wanting it for awhile, and been helping me rebuild it. im going to give it to him for free for being such a good guy.) Thanks all!

[TheSeeker]

Also, would I be better off rebuild the six and putting an auto behind it? would it get very different mileage? I would like the auto becaue my wife and daughter like to drive all my cars too, and they dont like the manual. Thanks!

[TheSeeker]

Nobodys ever done this before>?

[Tx Firefighter]

It's a common swap and I've done it a lot of times, but your questions aren't easy to decipher from your post.

If I follow you right, you'll need the engine and trans, engine frame stands, all front engine brackets and pulleys, auto trans crossmember, shift linkage, steering column, and radiator.

The wost part of the swap is the 6 cyl 3 speed truck will have a riveted crossmember beneath the bellhousing area. It must be completely removed for the V8, auto swap and replaced with the bolt in type automatic crossmember from your donor truck which goes under the tail of the auto transmission.

[TheSeeker]

Ok, thanks! Im sorry about not being clear. You were correct, I am wanting to take my fresh 350/th350 and put it in a truck that was originally 6cyl. I guess my question is now, would I be better off rebuilding the IL6 and can a auto transmission be mated to it? I assume the cross member would have to be changed regardless or whether the sbc goes in or not correct? (for the auto trans)

[Tx Firefighter]

Putting the automatic behind the six is a bolt on deal. The six and 350 share the same bellhousing pattern, flexplate, starter and all of that. Regardless of which engine you choose though, the automatic trans is gonna require the old crossmember be cut out (it's riveted in place) and the new auto crossmember used. You'd also still need to do the auto trans cooler and lines, shift linkage, and automatic steering column regardless of which engine.

[dmack91]

If the old LWB was set up for a V8 and auto, you should be able to swap the original parts from it to the swb. You could then take the 6cyl/3sp parts and give them to your brother to put in the LWB.

Just a thought.